Rats have been fed various combinations of tryptophan (D or L isomers), vitamin B6 deficient diets, and 2-fluorenylacetamide, in combination or in sequence in attempts to delineate the role of tryptophan metabolites as bladder carcinogens. Urines from these animals have been collected and are being analyzed for tryptophan metabolites to provide documentation of the effects of various dietary regimens on tryptophan metabolism. Rats have now been sacrificed and histological review of tissues will be accomplished in the coming year.